Can Anabolic Androgenic Steroids Cause Increased Body Hair?
Yes, anabolic androgenic steroids definitively cause increased body hair (hirsutism) as a direct consequence of their androgenic effects on hair follicles.
Mechanism of Action
Anabolic androgenic steroids (AAS) are synthetic derivatives of testosterone that exert potent androgenic effects throughout the body 1, 2. The growth of sexual hair is entirely dependent on the presence of androgens, which induce vellus follicles in sex-specific areas to develop into terminal hairs that are larger and more heavily pigmented 1.
The key pathophysiologic pathway involves:
- Conversion of testosterone to dihydrotestosterone (DHT) by 5α-reductase in hair follicles
- Binding of DHT to androgen receptors in follicular cells
- Transformation of small vellus hairs into larger, pigmented terminal hairs 1, 3
Clinical Evidence from Guidelines
The Endocrine Society's 2008 guidelines explicitly identify anabolic steroids as a cause of androgen excess and hirsutism 1. When evaluating hirsutism, clinicians must specifically consider "use of androgens or androgenic medications, such as anabolic steroids" as a causative factor 1.
The 2014 Endocrine Society guidelines on androgen therapy confirm that masculinizing effects including hirsutism are dose-dependent side effects of androgen administration 2. These effects occur predictably with androgen exposure.
Documented Effects in Athletes
Research on athletes using AAS consistently demonstrates increased body hair as a common adverse effect:
- Self-reported increase in body hair is among the most frequent side effects that male athletes experience with AAS use 4
- Examination of skin biopsies from AAS users shows dramatic hypertrophy of sebaceous glands and pilosebaceous units 5
- Hirsutism occurs alongside other androgenic effects including acne, oily skin, and androgenic alopecia 5
Time Course and Reversibility
Hair growth changes require approximately 4-6 months to become detectable due to the long anagen (growth) phase of hair follicles, with maximal effects appearing around 9 months 1. This delayed response is critical for patient counseling.
Drug-induced hirsutism from androgens is usually reversible after cessation of treatment 6, though the timeline for reversal follows the same prolonged hair cycle dynamics.
Clinical Distinction
It's important to distinguish true hirsutism (androgen-dependent hair growth in a sexual distribution pattern) from hypertrichosis (generalized excessive hair growth). AAS cause true hirsutism through their androgenic properties, affecting androgen-sensitive areas like the face, chest, abdomen, and back 1.
Common Pitfalls
- Don't underestimate the psychological impact: Hirsutism significantly affects quality of life and well-being, particularly in female athletes 7
- Recognize that effects are dose-dependent: Higher doses and longer duration of AAS use produce more pronounced hirsutism 2, 4
- Consider concurrent effects: AAS users typically experience multiple androgenic side effects simultaneously, including acne, seborrhea, and potential androgenic alopecia on the scalp 5
The evidence is unequivocal across multiple high-quality guidelines and research studies: anabolic androgenic steroids cause increased body hair through direct androgenic stimulation of hair follicles, with effects that are predictable, dose-dependent, and generally reversible upon cessation.